1. Field of the Invention
The present invention pertains to a battery pack, and more particularly, a nickel cadmium battery pack, or battery pack with a nickel alloy, metal alloy or metal flexible welding board, which allows for the welding of battery cells, electrical components and electromechanical components, including the battery cells directly to the flexible welding board. The welding is preferably by spot-welding.
2. Description of the Prior Art
In the past, battery packs, particularly nickel cadmium battery packs, have been assembled by hand where the batteries are spot-welded to each other by flat straps, such as stainless steel or nickel. Then, the contacts are placed into the battery pack housing, and the batteries are again connected by spot-welding the flat straps to the battery contacts. Finally, the electrical or electromechanical components such as thermistors, resistors, capacitors and any other components are connected along the process to the straps or the contacts, such as by spot-welding or soldering. This type of process is labor intensive, and takes considerable time and motion by a group of individuals to assemble each battery pack.
Prior art flexible circuits were sometimes not practical, as the circuits could sometimes not be easily mass-produced, nor could the flexible circuits sometimes be easily spot-welded. Prior art flexible circuits were not able to include all of the components, including the battery cells, the electrical components and the electromechanical components such as the battery casing contacts. Prior art flex circuits did not lend themselves to mass production for use in NiCad or other types of battery packs.
Prior art flexible circuits were usually a copper material on a polymer. Prior to etching of the copper material, the copper had to sometimes be protected, such as by plating with a tin lead or a tin nickel. This was an additional time consuming step Which added expense and labor.
Prior art standard flexible boards require soldering metal weld tabs to the board to allow battery cells to be welded to it thus adding expense and labor.
The present invention overcomes the disadvantages of the prior art by providing a unique and novel flexible welding board where all of the electrical components and electromechanical components can be spot-welded to the flexible welding board such as a polyester board for subsequent insertion into a battery housing or battery casing, thereby forming a battery pack. The elimination of the labor intensive operations of adding weld tabs prior to welding results in a significant cost savings, as well as allowing a more compact board design.